1. Field of the Invention
The present invention relates generally to power modules and, more particularly, to systems and methods for providing power to battery-powered devices.
2. Related Art
Electrotherapy devices are used to provide electrical shocks to treat patients for a variety of heart arrhythmias. For example, external defibrillators typically provide relatively high-energy shocks to a patient as compared to implantable defibrillators, usually through electrodes attached to the patient""s torso. External defibrillators are used to convert ventricular fibrillation or shockable tachycardia to a normal sinus rhythm. Similarly, external cardioverters can be used to provide shocks to convert atrial fibrillation to a more normal heart rhythm.
Conventional external defibrillators have been used primarily in hospitals and other medical care facilities. In such environments, the frequency with which a particular defibrillator is operated, referred to herein as the use model of the device, is significant, perhaps on the order of several times per week. While these external defibrillators have been known for years, generally they have been large and expensive, making them unsuitable for use outside of a medical facility. More recently, portable external defibrillators for use by emergency medical service (EMS) and other medically-trained first responders have been developed. These defibrillators allow medical care to be provided to a victim at the victim""s location considerably earlier than hospital defibrillators, increasing the likelihood of survival. To operate effectively in the intended mobile environment, portable defibrillators require a portable energy source. Several defibrillator and after-market manufacturers have provided battery packs for such defibrillators. These battery packs, which have traditionally been rechargeable due to the anticipated high frequency use model, are available with different chemistries such as lead acid, nickel cadmium, lithium ion and the like.
With recent advances in technology, portable defibrillators have become more automated, allowing even minimally trained operators to use such devices to aid a victim in the critical first few minutes subsequent to the onset of sudden cardiac arrest. Such portable defibrillators, referred to as automatic or semi-automatic external defibrillators (generally, AEDs), may be stored in an accessible location in a business, home, aircraft or the like. Due to the anticipated low use model of such defibrillators, as well as the increased diligence required of rechargeable battery packs, many conventional AEDs operate with a non-rechargeable battery pack. This is more common in recent history due to advances in battery technology that has facilitated the development of long life, high capacity, non-rechargeable battery packs.
One particular problem that arises using currently available portable defibrillators is that occasionally it may be necessary or desirable to operate the device in accordance with a use model different than that for which the defibrillator was originally designed. Currently available defibrillators are not amenable to accommodating changes in the use model by enabling the user to change the power source. One characteristic of defibrillators that prevents such a change in operation is the use of a charge controller in the defibrillator that implements a charging protocol to charge an battery pack while the battery pack is installed. Such charge controllers implement a single charging protocol suitable for charging a battery pack having cells of a specific chemistry. As a result, the charge controller selected when the defibrillator is manufactured is based on the chemistry of the rechargeable battery pack specified for use with the defibrillator. Thereafter, the defibrillator is restricted to using battery packs of the type and chemistry that can be charged by the implemented charge controller. This, in turn, makes it undesirable to operate the defibrillator in accordance with a use model other than that which the defibrillator was originally designed. On the one hand, the use of a high maintenance, rechargeable battery pack in a low use model is impracticable. Conversely, the use of a non-rechargeable battery pack in a high use model environment is prohibitively expensive.
What is needed, therefore, is a flexible approach for providing power to an electrotherapy device that does not restrict the type and chemistry of the battery packs with which it operates, and which can be configured to accommodate different device operations.
A number of embodiments of the invention are summarized below. It should be understood that the summarized embodiments are not necessarily inclusive or exclusive of each other and may be combined in any manner in connection with the same or different embodiments that is non-conflicting and otherwise possible. These disclosed embodiments of the invention, which are directed primarily to systems and methods related to power modules and devices that operate with such power modules, are exemplary embodiments only and are also to be considered non-limiting.
A device such as an electrotherapy device implementing the power management system of the present invention includes multiple power module receptacles each of which is configured to have installed therein at least one type of power module. A power distribution system selectively routes power provided by one or more installed power modules to components of the electrotherapy device. The types of power modules that operate in the power module receptacles include, for example, rechargeable battery packs, non-rechargeable battery packs and AC power packs. Selection of which power module is to be installed to provide power to the device at any given time may be determined based on various factors such as the status and capacity of the power modules, the anticipated use model of the device, etc. Advantageously, any combination of power modules may be concurrently installed in the power module receptacles to optimally support the anticipated use model of the device. In addition, as the use model of the device changes, so too can the installed power module selected to power the device.
Preferably the power distribution system also routes power between power module receptacles that include fully integrated, functionally self-contained power modules. For example, the rechargeable battery pack preferably includes a charge controller specifically designed to charge the battery pack in which it is implemented. This enables an AC power module and such a rechargeable battery pack to be concurrently installed in the device, connected to each other to enable the AC power pack to charge the rechargeable battery pack. This provides the significant advantage of eliminating the need to include an equivalent charge controller in the device itself.
In one embodiment, the power distribution system includes an internal network of power distribution buses that can be selectively connected to specified power module receptacles and device components. Independently controlled switches constructed and arranged to connect individual power modules to specific power distribution buses are also included. A power distribution manager may be implemented to determine a power management configuration and to control the switches to electrically connect specified power modules and device components to implement the power management configuration. The power management configuration may be determined based on any number of factors such as the intended use model of the device, the type of power modules installed in the power module receptacles, and an ability of the installed power modules to support the use model of the device.
In another embodiment of the invention, an electrotherapy device such as a portable defibrillator is disclosed. The device includes first and second power module receptacles. The first power module receptacle is configured to have installed therein a power module of a first power module type. The second power module receptacle is configured to have installed therein a power module of a second power module type. The device also includes an internal power distribution network configured to connect one or more of the installed power modules to device components. Individually controlled switches can be activated to electrically connect installed power modules to one or more power buses. A power management system controls the switches to connect selected installed power modules to the power distribution network.
In a further embodiment of the invention, a rechargeable battery pack is disclosed. The battery pack includes a housing with at least one battery cell and a charge controller mounted therein. The charge controller charges the battery cell using an externally-applied DC power. The battery cell may be of a particular chemistry while the charge controller is configured to charge battery cells of such particular battery chemistry. The chemistry of the battery cells may be, for example, lithium ion, lead acid, NiCd, etc.
In a still further embodiment of the invention, a set of power modules each configured to provide a DC voltage to a device when operationally installed therein is disclosed. In one embodiment, the set of power modules includes a rechargeable battery pack and a non-rechargeable battery pack. The rechargeable battery pack includes a first housing with one or more battery cells and a battery charger mounted therein. The battery charger applies to the battery cells a charging voltage derived from an externally-applied DC voltage. The battery cells generate a first DC voltage for use by the device. The non-rechargeable battery pack includes a second housing with one or more battery cells mounted therein. These battery cells generate a second DC voltage for use by the device. Preferably, the set of power modules also includes an AC power pack. The AC power pack includes a third housing, an AC-to-DC converter mounted within the third housing, and an electrical interface for providing an externally-applied AC voltage to the AC-to-DC converter. The AC-to-DC converter converts the applied AC voltage to a third DC voltage suitable for use by the device. In one embodiment, the first, second and third housings have a same form factor.
Various embodiments of the present invention provide certain advantages and overcome certain drawbacks of the conventional powered devices, particularly, electrotherapy devices. Not all embodiments of the invention share the same advantages and those that do may not share them under all circumstances. This being said, embodiments of the present invention provides numerous advantages some of which are noted above. These and other features and advantages of the present invention as well as the structure and operation of various embodiments of the present invention are described in detail below with reference to the accompanying drawings.